1. Technical Field
The present invention relates to the field of telecommunications trunk group selection and, more particularly, to providing telecommunications trunk group selection in accordance with customer preferences.
2. Description of the Related Arts
In the field of telecommunications switch design, it is well known to provide for the selection of idle trunks or other circuits such as service circuits for connecting calls to customers. The customer, for example, may be the provider of an airline reservation system. Such an airline reservation system may be provided via an automatic call distributor for distributing calls to service representatives manning service positions. To provide for the great number of incoming calls to such an airline reservation system, a plurality of trunk groups incoming to the customer may be provided from a toll switch through a local exchange carrier to the customer. Each trunk group may contain multiples of twenty-four trunks which may comprise, for example, T1 carrier channels.
Referring to FIG. 1, there is shown a toll network 100 comprising a plurality of toll switches such as toll switch 110. By way of example, toll switch 110 may comprise a #4ESS switch of Lucent Technologies, Inc. Toll trunks connect toll switch 110 with other toll offices via trunk circuits and facilities such as trunks of trunk groups 111 or 112. A network adjunct 115 may provide adjunct services in toll network 100 such as voice response unit (VRU) and dual tone multi-frequency (DTMF) signaling, reception and translation.
A caller desirous of obtaining an airline reservation may dial an incoming WATS telephone number such as 1-800-555-AIRS. Once the dialed number is received at an originating toll central office, for example, a #4ESS, the dialed number is translated into a routing number so that the caller may be routed through the network 100 to the customer interface 160. When the call reaches the destination toll switch 110, the several incoming trunk groups (four are shown) 125 are provided for connecting the caller via local exchange carrier (LEC) 150. Each trunk group, for example trunk group 120, may comprise twenty-four trunks, hereinafter referred to as blocks of trunks. Of the trunks in trunk group 120, several may be already busy and in use by other callers and some may be free.
Referring briefly to FIG. 2, there are pictorially represented N trunk blocks twenty-four (24) trunk circuits each, by way of example. Referring to trunk group 1, there are shown an indication of busy/idle status for all twenty-four trunks in each trunk block. The problem of the present invention relates to how to expeditiously pick an idle trunk circuit of a trunk block and how to pick a trunk block for selecting an idle trunk.
There are many and various ways of selecting a trunk block and an idle trunk. Typically, a toll switch will hunt for an idle trunk in blocks of twenty-four trunks. In the depicted example of FIG. 1, it may be assumed that there exist four trunk blocks of twenty-four trunks each. There may be a link list and a hunt list. The trunk blocks are maintained on a link list in memory. In one trunk selection algorithm, the trunk blocks may be jumbled, for example: 4, 2, 1, 3; in another, the trunk blocks may be in order, for example: 1, 2, 3, 4. One may continue to use trunk block #1 with each incoming call to the switch 110, for example, during low traffic periods when there are mostly idle trunks. It may be that the customer desirably wishes to have evenly spaced traffic over all the trunks of all the trunk blocks. In an alternative algorithm, the switch may hunt sequentially through all the trunk blocks until an idle trunk is found and then continue from that point with the next incoming call to be connected.
Continuing to track a given call to a customer 160, a trunk circuit is selected by a predetermined algorithm according to the prior art and the caller is connected typically to a voice response unit 161, such as a Lucent Conversant(TM) system. The system 161 speaks to the caller, prompts for a response and determines a caller selection, for example, from DTJF input, such as international reservations, and then an automatic call distributer of,customer interface 160, not shown, connects the call to an international service representative.
Certain customers may want a first in first out (FIFO) means of selecting trunks so that calls may be evenly dispersed among serving voice response units 161 on the customer premises. Others may want still other algorithms for trunk/trunk block selection. The trunk circuit selection algorithms known in the art comprise, for example, the following: lowest idle circuit first, highest idle circuit first, A- sequential (on the first call, select the first circuit, then the second circuit and so on), least used circuit, longest idle circuit, normal #4ESS selection algorithm and custom circuit selection. Others include most idle, least hunted; most busy, most hunted; and circular trunk hunt or circuit selection. Trunk circuit selection algorithms are many and varied and only limited by the imagination.
As suggested by these different types, the circuit selection algorithm may be switch dependent. That is, a #4ESS may have a preferred trunk circuit selection algorithm and a Northern Telecom digital multiplex switch a different one. In fact, there may be different trunk selection algorithms performed by each switch manufacturer: Siemens, Ericcson, Stromberg Carlson, Fujitsu and so on. Presently, trunk circuit selection algorithms may be switch dependent, that is, each manufacturer may prefer their own.
Since customers may not wish to be tied down to specific circuit selection algorithms, there remains a problem with the present telecommunications network that circuit selection algorithms, although many different algorithms exist, cannot be selected by customers or otherwise selected, for example, by time of day, traffic usage, day of week or circuit or trunk type.
In accordance with the principles of the present invention, the problems of prior art telecommunication network circuit selection criteria are solved by providing a plurality of circuit selection algorithms at a switching center that may be associated with a customer by the customer""s directory or routing number. Consequently, upon routing a call to the customer, a circuit selection algorithm selected and predetermined by the customer from the plurality of available and different algorithms may be applied for routing calls to that customer. Apparatus for providing a customer selectable circuit selection algorithm includes the provision in memory at the switching center of a table of possible different circuit selection algorithms, input means for receiving customer preferences and a controller for operatively connecting calls to the customer via circuits selected according to the predetermined selected circuit selection algorithm, predetermined by the customer.
In a further embodiment of the idle circuit selection algorithm features of the present invention, the customer may further determine certain times of the day and/or days of the week, high or low traffic usage characteristics, circuit or trunk type and the like for selecting one as opposed to another predetermined algorithm. Moreover, the customer may implement their own circuit selection algorithm of their own design via the same or different input means. The present invention is not limited to implementation in a toll network and will find application as well at a local exchange carrier or in a large private network.
These and other features of the present invention will become clear from an appreciation of the drawings and the following detailed description thereof.